Supreme Court en banc Decision 2019Da229202 Decided August 25, 2022 【Damages (Etc.)】

【Main Issues and Holdings】
[1] Requirements for satisfaction of the “necessity for preservation” to exercise an obligee’s right of subrogation and standards for determining whether or not the necessity for preservation has been satisfied
[2] In a case where: (a) the insured paid medical expenses to a health care institution for the provision of a discretionary nonreimbursable medical service and subsequently received insurance payouts related to the medical expenses by filing a claim against the insurer under a policy of actual medical expenses insurance; and (b) the medical service provided was subsequently deemed to be an unlawful discretionary nonreimbursable medical service, which is null and void, and thus did not constitute a ground for payment of insurance payouts under the actual medical expenses insurance contract, whereby the insurer was entitled to file a claim for restitution of unjust enrichment corresponding to the amount of insurance payouts against the insured, whether the necessity for preservation is satisfied, regardless of the obligor’s insolvency, in the obligee’s lawsuit filed in substitution of the obligor, in which the insurer-obligee-subrogee exercises, in place of the obligor-insured-subrogor, the said insured-obligor-subrogor’s claim for restitution of unjust enrichment corresponding to the amount of medical expenses against the health care institution, a third party debtor which owes a debt to the obligor, to preserve the insurer-obligee-subrogee’s foregoing claim for restitution of unjust enrichment (negative)